On Fri, Oct 24, 2003 at 04:15:28PM +0100, Luis Moreira wrote:
> Hello Guys
>
> I need to compare to numbers to see which of them is higher can someone
> point me on the right direction?

What sized numbers?

The basic comparison plan is always to subtract the numbers. So if we are
comparing A and B then we look at the result of A-B (and the STATUS flags
C and Z)

If A-B > 0 then A>B   C=1  Z=0
if A-B = 0 then A=B   C=1  Z=1
if A-B < 0 then A<B   C=0  Z=0

So do the substraction, noting that on the PIC that SUBWF subtracts W from F
and not the other way around.

For multibyte compares you start with the highest byte. If the answer of Ax-Bx,
where Ax and Bx are the bytes you're currently comparing, is not Z=1, then
you have the answer in the C flag. However if the answer is Z=1 then you have
to step down to the next byte in each of the numbers and repeat the comparison.

I didn't write any code becayse I don't think there's enough information to
do so. However these guidelines should lead you in the right direction.

BTW I pulled the C and Z flag values directly out of the 16F62X datasheet under
the SUBWF instruction on pg 119.

BAJ

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